항만 내 항행선박 효과에 대한 CFD 연구

Abstract

As environmental regulations from the International Maritime Organization (IMO) have tightened, there is increasing interest in LNG (Liquefied Natural Gas)-powered ships, which use LNG as an eco-friendly fuel. To further advance LNG-powered ships, establishing LNG bunkering infrastructure, which supplies LNG fuel, is essential. In response, the Korea Research Institute of Ships and Ocean Engineering (KRISO) developed and constructed an LNG bunkering ship with a capacity of 500 cubic meters in 2022. Furthermore, research into simultaneous operations (SIMOPS) for LNG bunkering―carrying out both LNG bunkering and cargo handling of LNG-powered ships simultaneously―is necessary to ensure safe and efficient procedures. LNG bunkering simultaneous operations are feasible when the powered ship is moored at a quay. To determine the criteria for allowing SIMOPS, it is necessary to assess mooring stability considering environmental ocean loads. In ports where many ships are navigating, passing ships often sail close to moored ships, leading to interactions between them. One key factor in these interactions is the generation of ship wake waves. The characteristics of these waves vary depending on the passing ship's speed, size, separation distance between ships, and water depth. In confined waters like ports, where depth and sidewalls are limited, wake waves can have a significant impact on the operational safety of moored ships. In order to ensure that the moored ship can safely conduct its operations, it is essential to assess the influence of passing ships.

In this study, computational fluid dynamics (CFD) was used to analyze the effects of passing ships on the moored ship. Numerical analysis was conducted using the URANS (Unsteady Reynolds-averaged Navier-Stokes)-based Star-CCM+ version 15.04, and the movement of passing ships was modeled using the overset mesh method. The simulation results were validated with benchmark test data presented at MASHCON 2022. The hydrodynamic forces acting on the moored ship, such as the surge force (X), sway force (Y), and yaw moment (N), were analyzed. Key results include variations in fluid forces, wave heights, and pressure distribution on the free surface and the moored ship. Additionally, parametric studies were conducted on the passing ship's speed, separation distance between ships, water depth, and the gap between the moored ship and the quay wall. To ensure the moored ship can conduct its operations safely, it is critical to assess the effects of passing ships.

In this study, computational fluid dynamics (CFD) was employed to analyze the impact of passing ships on a moored ship. Numerical analysis was conducted using the URANS (Unsteady Reynolds-averaged Navier-Stokes)-based Star-CCM+ version 15.04, with the motion of the passing ships modeled using the overset mesh method. The simulation results were validated against benchmark test data presented at MASHCON 2022. The hydrodynamic forces acting on the moored ship―including surge forces (X), sway forces (Y), and yaw moments (N)―were analyzed. Key outcomes included changes in fluid forces, wave heights, and pressure distribution on the free surface and moored ship, compared based on the relative positions of the passing and moored ships. Additionally, parametric studies were conducted to investigate the effects of the passing ship’s speed, separation distance between ships, water depth, and the gap between the moored ship and the quay wall.